PLEASE NOTE:  These APRSdos maps were produced as a public service for 
Amateur Radio use and Emergency Preparedness by NOFARS, The North Florida Amateur Radio Society.  These maps provide street level coverage of all seven counties (Baker, Bradford, Clay, Duval {Jacksonville}, Nassau, Putnam, and St. Johns) of the Florida Crown District.  These maps may be distributed without charge so long as credit is given to NOFARS for their funding and Alan Crosswell, N2YGK, as the author.

README -- Documentation for the local area APRS map maintainer.
See also, INTRO, a short introduction to using these maps.

APRSdos detailed street maps from US Census TIGER/Line 1995 files.
Generated by Alan Crosswell, N2YGK, n2ygk@weca.org using tig2aprs.
If you would like maps like these for another county, please contact
me for more info.

The zip files
-------------

The distribution is in a bunch of zip files meant to be unzipped
relative to the APRS main directory.

fl??map#.zip    - ?? County, FL, where ?? is one of:
fl??win#.zip    - ?? County, FL, where ?? is one of:
  du            - Duval County, FL
  cl            - Clay County, FL
  sj            - St. Johns County, FL
  na            - Nassau County, FL
  pu            - Putnam County, FL
  ba            - Baker County, FL
  br            - Bradford County, FL

and # is 1 or 2 (the files are split up to fit on floppies).  fl??win#
is a map to use with WinAPRS/MacAPRS and is not needed for APRSdos.
The zips are in 1.44MB chunks so they can fit on a 3.5" floppy.

Within each zip file are the following subdirectories:

maps            - contains the map files
maplists        - contains the maplist files
tig2aprs        - miscellaneous junk that you can unzip and look at
                  but not necessary for use with APRSdos.

To get setup on APRSdos, CD to the APRS directory and UNZIP each of
the files.  For example, for Duval:

cd \aprs
unzip a:fldumap1.zip maps/* maplists/*
unzip a:fldumap1.zip maps/* maplists/*

More details about the contents of the subdirectories follows:

MAPS - APRSdos map files
-------------------------

Maps rendered at ranges of 16,8,4,1 miles plus one big APRSdos map.
Naming scheme is:

fl??h000.map    - 32 mile map radius (one map)
fl??g000.map    - 16 mile map radius (one map)
fl??8###.map    - 8 mile map radius (several maps)
fl??4###.map    - 4 mile map radius (several maps)
fl??1###.map    - 1 mile map radius (hundreds of maps)

?? is one of du,cl,sj,na
### is a 3-digit automatically generated (meaningless:-) map number

MAPLISTS - Maplist files
------------------------

maplist.du?     - a set of maplists for Duval County
maplist.cl?       and so on for Clay, 
maplist.sj?       St. Johns, and 
maplist.na?       Nassau

Where ? is one of blank,A,1,2,3,4

maplist.xxA     - All maps.  This maplist is too large to actually use
                  with DOS aprs which has a 169 maps per maplist limit
                  and is meant solely as a reference for you to cut and
                  paste your own maplists together from.  In fact, it is
                  not even a true maplist since it is missing the header
                  lines.

maplist.xx      - All maps with no overlaps.  This gives you full coverage
                  but you have to HOME at the crosshair to see each map.
                  Panning (tracking, etc.) off the crosshair will cause
                  APRSdos to back off to the next larger (less detailed)
                  size.

maplist.xx?     - Where ? is one of 1,2,3,4 for the NW,NE,SE,SW quadrants.
                  Full coverage (maps plus 3 overlays for each).  This
                  maintains the same level of detail when panning across
                  maps zoomed in at 1/2 the map scale.  For example, at
                  the 1/2 mile scale, you can pan relatively smoothly
                  across the screen as APRSdos automatically loads the
                  next map that fully encloses the viewing area.  Due to
                  maplist size limits, all detail maps cannot fit in a
                  single county-wide mapllist.

Each maplist starts with what was in MAPLIST.FL2 which is a Florida statewide
maplist found in:

ftp://ftp.tapr.org/tapr/SIG/aprssig/files/maps/PCMaps/flmaps02.zip

You also may want to acquire the following maps if you don't already have them:

ftp://ftp.tapr.org/tapr/SIG/aprssig/files/dosstuff/APRSdos/semaps12.zip
ftp://ftp.tapr.org/tapr/SIG/aprssig/files/dosstuff/APRSdos/emaps13.zip


TIG2APRS - Other files
----------------------

The following files are in the tig2aprs directory:

log.??#         Execution log from tig2aprs showing what it did.
                ?? = county, # = range (h,g,8,4,1,w)
flxxwin.zip     Contains a single large DOS-format map, flxxw000.map,
                which can be used with WinAPRS or MacAPRS.  This map
                can have as many as 100,000 data points.
maplist.xxa     The reference list of all APRSdos maps supplied.  Use
                as a source of mapnames when customizing your own
                maplists.

Maplist details
---------------
Each maplist file line is commented with details that will help you
manipulate the maps.  Except for the root map, each maplist
entry is either a quadrant of a parent map which was tiled because it
had too many datapoints, or an overlap of a base map.  You can toss
all the overlaps for example and still have full coverage; just not
smooth panning.

Comment examples:

..., NW quadrant of fldu8000
..., E overlap of fldu1018

The map referenced for quadrants doesn't actually exist, since it was
split into 4, but you can see more about it in the log file.

Map details
-----------
Maps have been generated at several levels of detail, which for
lack of a better term, are designated by the map range in miles
for which they seemed to fit.  The levels are:

>16 - Major features only such as interstate highways, oceans, large rivers.
  8 - Adds major highways.
  4 - Adds minor highways.
  1 - Full street detail

Since APRSdos limits a given map file to 3000 data points, it is impractical
to have a reasonable looking map with full detail at any greater than a 1
mile range.  In certain dense urban areas the best one gets is a .5 mile
map range.  You will see some of these near the center of Jacksonville.

If you actually read a map file in a text editor, you will see a few
items worth noting:

In the comment block you'll see something like this:

      Map generated by tig2aprs from 1994 US Census TIGER/Line.
      tig2aprs (c) 1996,1997 Alan Crosswell N2YGK
      map has 2965 points f=20 wf=0.107 sf=0.165 

The third line shows the number of data points, how badly "fuzzed" the
map was (how far apart two data points can be and still be considered
the same. f=20 is the worst I will settle for); what percent size a
water body had to be to not be filtered out of the map (small lakes
that cover less than 10.7% of the map area were tossed); and a factor
that I can't explain to myself even that shows how close the slopes of
two line segments have to be in order to be collapsed into one (saving
a data point).

Each map feature is commented with details as well.  For example:

 3 ,(H11)Alligator Creek  84106848

This is an APRS color "3" (blue; see README\MAPMAKIN.TXT) feature.
The Census Feature Class Code is H11 (perennial stream or river),
"Alligator Creek" is the name (according to the Census records) and
the 84106848 is the unique TIGER/Line ID (TLID) of the feature (or one
of the features when they get chained together).  Note that similar
features that are end-to-end are glued together to save data points,
so the TLID is only for one end of the chain.  There are probably
20 or more TLIDs associated with the feature.

There are also a bunch of labels at the end of some map files which
correspond to names of places that come from the TIGER/Line data.
Appropriate APRS special symbols are included.  You will frequently
find 2 or 3 words stacked one above the other.  This is because APRSdos
is restricted to a 12 character label, so longer multi-word names get
split up by tig2aprs.

$/ENassau,30.538187,81.819466,4.0
Village,30.537394,81.819466,4.0
Ratliff,30.536601,81.819466,4.0
Jones,30.561619,81.860252,2.0
Cemetery,30.560826,81.860252,2.0

The labels come from the US Census concepts of places, key geographic
locations, and point and area landmarks.

More info
---------
Source code and documentation for the free program that generates
these maps is available at http://www.cloud9.net/~alan/ham/aprs.

Information about the US Census TIGER/Line data can be found at 
http://tiger.census.gov.




